Hi Op, I've been in your shoes...I read ALOT of threads and studied probably a good 2 months before I took the plunge, and I have NOT looked back. Here was the thread that helped the most:
http://www.longhaircareforum.com/showthread.php?t=167723
Here are a few other threads that helped as well:
http://www.longhaircareforum.com/showthread.php?t=194049
(while I never accessed the download she had available the info is still GREAT!!)
http://www.longhaircareforum.com/showthread.php?t=172511
I also went to what I considered really good resources based on their posts in the Ayurvedic Support thread: Aggie and FlowingLocks
My Ayurvedic Reggie is as follows:
Prepoo w/ Ayurvedic Oil mixture of:
Amla Oil
Bhringeraj Oil
Brahmi Oil
Vatika Coconut Oil
Shikakai Oil
100%AVJ
I have a pre mix of in a container. I put two tablespoons of this mixture into the foot of a pair of cut stockings and proceed to steep. The mix consists of:
Amla powder (1 tblsp) can be acidic- promotes growth, controls hair loss and graying
Maka powder (2 tblsp) conditioning powder- makes hair dense, promotes growth, cures Alopecia
Brahmi powder (2tblsp) conditioning powder- helps to darken, and make hair more dense, strengthens hair root and stops premature graying
I rinse using Suave Humectant or VO5, cowash using AM, then DC using KC Humecto (recently started mixing JBCO with this and I'm in love
)
Good Luck Op, but please do your research, it's worth it in the end.
ETA: Sorry, I forgot you also questioned why.....I'm guessing that was a why use whatever powders you are using, if so I've added what each of my powders is known for.